1. Field of the Invention
The present invention relates to the field of recycling apparatus for recovered environmental hazardous materials. More particularly, the present invention relates to the field of apparatus for controlling the filling of recycling storage tanks with recovered refrigerant used in refrigeration equipment.
2. Description of The Prior Art
Most commercial, industrial, residential and automotive air conditioning and refrigeration equipment operate with various types of refrigerants. The most common types of refrigerants are Chloro-Fluoro-Carbon ("CFC"), Hydro-Chloro-Fluoro-Carbon ("HCFC") and Hydro-Fluoro-Carbon ("HFC"), including commercial refrigerant products, such as R-11, R-12., R-22, R-500, R-502 and R-134a.
In early air conditioning and refrigeration equipment, the refrigerants such as CFC are disposed after they have been used for a certain period of time, and residuals of refrigerants are often directly vented to the atmosphere. Due to the increased awareness of the hazardous effect of CFC to the environment, for example the general effect of ozone depletion in the atmosphere and particularly the "green house" or global warming effect, stricter environmental protection legislation and regulations now require that the refrigerants must be recovered and recycled.
The refrigerants from commercial, industrial, residential and automotive air conditioning and refrigeration systems are collected and recovered through refrigerant recovery devices. Particulates, moisture, acid and other substances are removed and the refrigerants and processed into useable condition. Recovering tanks are utilized in the process of the refrigerant recovery for containing, transportation and recycling purposes.
A typical refrigerant recycling tank should be filled up to 80% full, and any more filling above that level is dangerous for storage and transportation due to the possibility of tank rupture. However, the majority of refrigerant recycling tanks available on the market today usually do not have any self-contained gauge, which makes it difficult to control the fill-up level. On the one hand, the recycling tanks should not be over-filled with recovered refrigerant because that is dangerous. On the other hand, the recycling tanks should not be under-filled with recovered refrigerant because that is inefficient.
In prior art, this problem is solved mainly by two methods. One method is to connect a sensing gauge in series with the inlet hose from a recovery unit. This method requires that the operator of the refilling process constantly observe the readings on the gauge and then manually terminate the process when the gauge reaches a critical reading. Another prior art method is to place the refrigerant recycling tank on a weighing scale and observing the weight of the tank while it is filled-up. The maximum allowable gross weight will be 80% of the water capacity weight of the refrigerant plus the tare weight of the tank. One problem with this method is that the empty tanks weigh different amounts. The operator must weigh the empty tank, calculate the weight of the tank when it is eighty percent (80%) full, and then set an appropriate cutoff point. This process is subject to operator error and is also time consuming.
The prior art manual control method has many disadvantages, including reducing the efficiency of the process and increasing the inaccuracy due to human error. It is desirable to have a refrigerant recycling tank equipped with protective devices, which can automatically terminate the flowing of refrigerant from the recovery unit to the tank when the latter is 80% full.